Ok, here is an example....on my homepage all the videos in the videoplayer are doing this.
www.nutkrackervideos.com, but this also happens in the component. Sometimes it seems as though Youtube changes the urls, but I am not sure.
The Longtail adverts should not affect this. Does it happen consistently with the same videos, or only occasionally? Once you see this message for a video, does it ever play again afterwards? I've looked at a few videos but not seen that message.
Sometimes the videos come back and play later, sometimes they don't. It is usually not the some videos.
What is the "official" youtube plugin? Is it the one that comes with the hwdmediashare package?